Bret Michaels fans were stunned when he performed the 80s Poison classic "Every Rose Has Its Thorn" on Wednesday's American Idolfinale.

So were his doctors.

"The doctors, I didn't tell them I was going to do this," he told UsMagazine.com. "I never told them I was coming here. They're going to find out in a few minutes!" As for his family, "I may not have told them, either," he added.

The new Us Weekly (on newsstands now) reports that the 47-year-old rocker and father of two — who nearly died after suffering a "warning stroke" and a brain hemorrhage in April –- has been worrying friends and family that he is putting his health at risk by refusing to put the breaks on his hectic schedule. "Just based on watching him, you could tell his body is not where his spirit is," his younger sister Michelle Sychak tells the new Us Weekly.

At the Idol finale, Michaels told Us, "To be honest, there's still obviously a lot of pain I’m still experiencing … [but] I feel great.

"Here’s the thing," he added, "they have not said everything’s OK. I’m running about 75 percent realistically, physically, but in my soul and my heart, I feel great. "I needed to do this tonight, just to come here," said Michaels, who told Us that he was first approached to perform on the Idol finale months ago before he got sick.

"It’s my first musical performance back and after this, I’m hoping to go out on the road, and I’m really looking forward to it."

On Friday, he told Us he is going to attempt to do a show in Biloxi, Miss. "I’m going to see how that goes and just take it a few shows at a time," he told Us.

He said he "was so excited" to return to the stage for Idol. "Later on, I may collapse, but right now, I feel great."

While performing, "my heart was pumping," he told Us. "I got on stage, first of all, the fans and friends and family were all here. It was such an awesome feeling to see everyone screaming and cheering and singing along with the song. I was like, 'Hey, that’s three generations out there, that’s all I’ve wanted to do is have a great music career and to be able to do that, 20-some years later, that’s a great feeling.